JP2006201635A - Optical photographing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in which, since a red component is absorbed underwater, when photographing is carried out with abundant outside light taken in, an image with uneven color due to outside light is formed such that color is enhanced with a green or blue component and also an optical photographic equipment tends to be hand shaken because both a subject and a photographer are floating in underwater photographing. <P>SOLUTION: In a program automatic mode, flash control is assigned to the control of automatic light emission with low luminance. In an underwater wide mode and underwater macro mode for underwater photographing, forcible light emission is controlled. A low speed limit second count for a shutter in the underwater wide mode and the underwater macro mode is set higher than that in a program automatic mode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical photographing device such as a digital camera having a land photographing mode and an underwater photographing mode, and more particularly to an optical photographing device capable of photographing an underwater photograph in the underwater photographing mode.

Digital cameras and digital video cameras (including those for news reports and movies) are included as optical photographic equipment that has shooting modes (underwater shooting modes) suitable for underwater shooting in addition to normal shooting modes (land shooting modes). ) Etc. are known. In underwater photography for photographing an underwater subject, the red component of light rays (external light) is absorbed more than other color components, so that the photograph has a different hue from the photographer's image. The degree of absorption increases as the water depth increases and the distance from the subject increases.
For example, in Japanese Patent Application Laid-Open No. 6-351525, when a subject is underwater, the white balance close to natural light is adjusted based on the water depth of the subject, the distance to the subject, and the white balance around the digital camera. An electronic still camera (digital camera) that emphasizes the red component is disclosed.
Japanese Patent Laid-Open No. 6-351025

In the above Japanese Patent Laid-Open No. 6-351025, since the red component absorbed in water is supplemented to achieve a white balance close to natural light during underwater photography, the color looks as if it was taken on land despite underwater photography. There is a problem that the quality of underwater photography is impaired.
Underwater photography is for taking pictures of living creatures such as fish, shellfish, underwater animals, and underwater scenery. The subject and background are different from those for land photography (land photography), and different from land photography. Because there is a lot of fun, it doesn't make any sense to lose the underwaterness in underwater photography.
Also, since the red component is absorbed more than the other color components, if you take a lot of external light to capture the exposure, the green and blue components will appear and the color will be biased by the external light. It becomes an image and an image with good color balance cannot be obtained.
Further, in underwater shooting, both the subject and the photographer are in a floating state and are constantly moving, so that camera shake is likely to occur, and shooting without camera shake is difficult.
An object of the present invention is to provide an optical photographing apparatus capable of photographing an image with a good color balance and no camera shake.

  The optical photographing apparatus of the present invention is characterized in that the flash is forcibly emitted when the underwater photographing mode is selected, and the low-speed limit time of the shutter is shifted to a higher speed than when the land photographing mode is selected. .

  According to the first aspect of the present invention, when the underwater shooting mode is selected, the flash device is forced to emit light so as to reduce the dependence on external light, and the low speed side limit time of the shutter is shifted to the high speed side. As a result, the dependence of external light is reduced, and there is no uneven color coverage due to external light, so that an image without camera shake having a well-balanced color balance can be taken.

  According to the second aspect of the present invention, when the underwater shooting mode is selected, the low speed side limit time is fixed to the high speed side as compared with the program auto mode, and flash shooting is performed. As a result, the effective distance of flash light becomes longer and the shooting range of the flash light is expanded.

    According to the third aspect of the present invention, when the underwater shooting mode is selected, the white balance is adjusted by the adjusting means so as to emphasize the blue component, so that it can be seen that the image is taken underwater even if it is bluish. Is obtained.

  According to the fourth aspect of the present invention, since the adjusting means has an auto balance function for adjusting the white balance based on the photographed image, an image having a natural hue is photographed.

  According to the fifth aspect of the present invention, since the white balance can be adjusted based on the color temperature in fine weather in the underwater shooting mode, the blue component is emphasized to give a bluish hue, and the underwater shooting is performed. An image can be obtained at a glance.

  In the present invention, when the underwater shooting mode is selected, light is forcibly emitted, and shooting is performed by shifting the low speed side limit time of the shutter to the high speed side.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of an optical photographing apparatus embodied as a digital camera. As shown in FIG. 1, the digital camera 10 includes a photographing lens 12, an image sensor (CCD) 14, a control circuit 16, a white balance calculation. Circuit 18, recording medium 20, memory 22, release switch (release SW) 24, zoom switch (zoom SW) 26, flash 28, liquid crystal display (LCD) 30, water depth gauge 32, power switch (power switch SW) 34, mode dial (Mode SW) 36, a cross key (selection key) 38, a shutter 40, and a photometric sensor 42 are provided. The digital camera 10 may be a digital camera including an underwater shooting mode in addition to the land shooting mode, which is covered with a waterproof protector, and is not limited to a dedicated underwater shooting machine (underwater camera).

  The subject 44 is imaged on the CCD 14 through the photographing lens 12 and the shutter 40, and image data of an analog signal that has been subjected to photoelectric conversion is input to the control circuit 16. The light quantity of the subject 44 (subject light quantity) is detected by the photometric sensor 42, and the opening / closing time (shutter time) of the shutter 40 is controlled according to the detected subject light quantity. The control circuit 16 has a CPU and controls the operation of each component of the digital camera. Image data from the CCD 14 is A / D converted and displayed on a liquid crystal display (LCD) 30. When the release SW 24 is pressed, the image picked up by the CCD 14 is taken into the control circuit 16 and temporarily stored in the memory 22. Then, the white balance calculation circuit 18 performs white balance calculation on the digital image (image data) in the memory 22, corrects the color, and writes it on the recording medium 20. If the subject light quantity is insufficient, the flash 28 is caused to emit light, and the subject 44 is irradiated with flash light for photographing. The depth gauge 32 measures the depth of water.

  2 shows the external shape of the digital camera 10, FIG. 2A is a plan view, and FIG. 2B is a rear view. The operation of the various SWs will be briefly described with reference to FIG. 2. First, when the power SW 34 is pressed, the power is supplied, the control circuit 16 and other components are activated, and the photographing is ready. Next, the shooting mode is set with the mode dial 36. In the mode dial 36, the program auto mode indicated by P is set as a standard setting. In this photographing mode, the aperture and shutter speed are automatically adjusted, and photographing with an appropriate exposure can be performed simply by pressing the release SW 24. In addition to the program auto mode, a scene mode and a playback mode can be set with the mode dial 36. When the mode dial is rotated to the position of the scene mode and the cross key 38 is operated, the portrait mode, the landscape mode, Scene modes such as night view mode, beach & snow mode, party mode, and underwater mode are sequentially displayed on the LCD 30, and the corresponding scene mode is selected and set by pressing the OK button 38a at the center of the cross key. When the corresponding scene mode is set, exposure conditions such as aperture, shutter speed, zoom, and light emission are automatically controlled and set by the control circuit 16.

  The playback mode is also set by the mode dial 36. In the playback mode, an image stored in the recording medium 20 is displayed on the LCD 30 and played back. For example, forced light emission, exposure correction, image deletion, image quality mode change, and the like are set and executed by the cross key 38. In addition, the zoom SW 26 zooms up or down the subject 44 to set an optimum focal length. Note that the operation of various SWs is an example, and the present invention is not limited to this.

  FIG. 3 shows a screen of the LCD 30 for selecting and setting the underwater shooting mode. FIG. 3A shows a screen before selection by the OK button, and FIG. 3B shows a screen after selection. In the embodiment, it is assumed that an underwater wide mode and an underwater macro mode can be set as the underwater shooting mode, and a waterproof protector (not shown) is covered with the digital camera 10.

  For underwater photography, the mode dial 36 is set to the scene mode, and the underwater wide mode or the underwater macro mode is selected and set by operating the cross key 38. In FIG. 3, for the sake of simplification, the scenes a to d are sequentially displayed on the LCD 30 by operating the cross key 38, the underwater wide mode is displayed in the scene b, and the underwater macro mode is displayed in the scene c. In scene a, the party mode is displayed.

  More specifically, when the cross key 38 is operated with the mode dial 36 as the scene mode, the underwater wide mode is selected in the scene b and the underwater macro mode in the scene c in the scenes b and c, as shown in FIG. Visually displayed, the OK button 38a in the center of the cross key is pressed to select and set the scene b or c. Then, as shown in FIG. 3B, the explanation of the underwater wide mode is displayed on the LCD 30 for the scene b and the explanation of the underwater macro mode is displayed on the LCD 30 for a certain time in the scene c. Is displayed. As described above, when the corresponding scene mode is set, the exposure conditions such as the aperture, shutter speed, zoom, and light emission are automatically controlled and set by the control circuit 16. Therefore, immediately by pressing the release SW 24, It can shoot quickly, easily and without failure. Various conditions in the underwater wide mode and the underwater macro mode are illustrated in FIG.

The characteristic setting in FIG. 4 is the setting relating to the flash control and the shutter speed on the low speed side limit time (also referred to as camera shake limit time).
In other words, for flash control, in program auto mode, so-called low-brightness automatic flash control is performed automatically when the subject brightness is low, and forced flash control is performed in underwater wide mode and underwater macro mode. Is done.
Further, the low speed side limit time is changed from 1/30 seconds to 1/100 seconds according to the zoom position in the program auto mode, and is fixed to 1/200 seconds in the underwater macro mode. When the underwater is wide, the low speed side limit time is fixed to 1/30 second.
Although the zoom position in the underwater macro mode is basically suitable for the tele side, it may be changed by the photographer's zoom operation. In this case, the speed may be changed at the same time depending on the zoom position, but it is desirable that the speed is higher than that in the program auto mode, for example, 1/60 seconds to 1/200 seconds.

  In this way, in the underwater wide mode and underwater macro mode, the shutter speed on the low speed side is set higher than in the programmed auto mode suitable for shooting on land, so both the subject and the photographer are floating. Even in underwater shooting, where camera shake is likely to occur, camera shake is prevented and shooting without camera shake becomes possible. In particular, in the underwater macro mode, fish such as anemone fish that move quickly are often photographed. In this case, photographing without subject blurring can be performed by shifting the shutter speed to the high speed side. It is also conceivable to use a high-magnification close-up lens. In this case, camera shake can be prevented by shifting the shutter speed to the high speed side.

  If the brightness is low during underwater photography, the red component is lost from the external light, and if a large amount of external light is taken in order to satisfy the exposure, the green and blue components are colored. However, in underwater wide mode and underwater macro mode, forced light emission with a higher shutter speed is used, so the dependence of external light is reduced and there is no uneven color coverage due to external light, and images with a well-balanced color are taken. Is possible.

  The low-speed limit time is fixed at 1/200 seconds in the underwater macro mode and 1/30 seconds in the underwater wide mode, and flash photography is performed on the high speed side compared to the program auto mode. When the influence is reduced and the influence of the flash light is relatively increased, the effective irradiation distance of the flash light is increased, and the photographing range by the flash light is widened.

  FIG. 5 shows a flowchart for setting the scene mode. First, the mode dial 36 is turned to switch from the standard program auto mode to the scene mode (S100). In the scene mode, the scene a is first displayed on the LCD 30 (S101). Since the scene a is a party scene, the scene is changed by pressing the cross key 38 (S102), and the next scene b is displayed (S103). , Return to S102. If shooting in the underwater wide of the scene b, it is not necessary to change the scene. Therefore, the process proceeds from S102 to S104, the OK button 38a of the cross key is pressed, the scene mode is fixed to the underwater wide mode, and the conditions corresponding to the underwater wide mode are set. (See FIG. 3C) is automatically set (S105) and set (S106).

  When shooting underwater macro instead of underwater wide, the scene is changed by further pressing the cross key 38 in S102, the next scene c (underwater macro) is displayed (S103), and the underwater macro mode is determined (S104). In FIG. 3C, conditions corresponding to the underwater wide mode are automatically set (S105) and set (S106).

  Auto white balance and manual white balance can be set in the digital camera 10. With auto white balance, the color components are automatically adjusted so that the light source at the shooting location is converted to sunlight in the daytime so that it appears in natural colors. As a result, an image having a natural hue can be obtained. In manual white balance, the color temperature of the light source is selected and set by the cross key 38 and the OK button 38a according to the shooting conditions by selecting and setting the shooting location or the shooting light source, corresponding to the shooting atmosphere. An image is obtained. For example, the color temperature of sunlight (natural light) in clear weather, which is a standard for white balance, is 5500K, the sunlight in cloudy weather is 7500K, the incandescent bulb is 3000K, and the fluorescent lamp is 4000K.

  When the release SW 24 is pressed, the subject image captured by the CCD 14 is taken into the memory 22 via the control circuit 16. Then, white balance is applied to the image data read from the memory 22 by the white balance arithmetic circuit 18 under the control of the control circuit 16. That is, the output of the color components red R, green G, and blue B is extracted from the image data read from the memory 22, and the color distribution (B / G distribution with respect to R / G) is calculated, and this color distribution is analyzed. Thus, the type of light source (color temperature) is estimated. A table of coefficients (correction coefficients) for various light sources (color temperatures) is stored in the white balance control circuit 18, and the coefficients α of red R, green G, and blue B are based on the light source estimation results by color distribution analysis. , Β, γ are referenced and selected. Then, if the outputs of red R, green G, and blue B are multiplied by coefficients α, β, and γ, an image having a natural hue as a whole can be obtained.

  If the auto white balance is activated during underwater shooting, an image with a natural color under natural light will be shot despite underwater shooting, and the underwater shooting will be lost. Therefore, in the embodiment, when in underwater shooting mode, the white balance is adjusted to emphasize the blue component to express the underwater shooting quality, and when the underwater shooting mode is set, auto white balance functions. Without being used, the coefficients αs, βs, and γs specific to underwater photography are automatically selected from the table of the white balance control circuit 18 by the control circuit 16 and used. The coefficients αs, βs, and γs are set with a balance that enhances underwater photography, that is, a balance that enhances the blue component to obtain a bluish hue. Therefore, if the outputs of red R, green G, and blue B are multiplied by the coefficients αs, βs, and γs, the blue color is emphasized as a whole, and an image of the atmosphere taken in water is taken.

The coefficients αs, βs, and γs of red R, green G, and blue B in underwater photography are obtained on the basis of the color temperature of sunlight in water (5500K), and in the state that the color temperature of the light source is set to 5500K, The subject 44 is imaged, and the light quantity ratios of the red R, green G, and blue B outputs R ₅₅₀₀ , G ₅₅₀₀ , and B ₅₅₀₀ are calculated to be the same. That is, it is calculated from the following equation (1). It should be noted that βs = 1 and that the calculation is based on the green component.
R ₅₅₀₀ * αs: G ₅₅₀₀ * βs: B ₅₅₀₀ * γs = 1: 1: 1: (1)

  FIG. 6 is an example of the coefficients αs, βs, and γs in the table of the white balance control circuit 18. In the underwater macro, the subject is located on the entire screen and the range in which the water is reflected is often narrow, and therefore smaller than the underwater wide. A coefficient is set (γst <γsw). If βs = 1, γs ≧ 1 and γs ≧ αs.

  The coefficient γs of blue B may be changed in accordance with the shooting angle of view when the zoom lens (shooting lens 12) is changed and the shooting angle of view is changed. Further, the coefficient γs of blue B may be changed according to the depth measured by the water depth gauge 32. If the coefficient γs is changed and calculated according to the shooting angle of view and depth, it is possible to perform shooting in which the degree of enhancement of the blue component is adjusted in accordance with the shooting angle of view and depth.

As described above, in the shooting mode suitable for underwater photography (underwater wide mode, underwater macro mode), the flash 28 is forced to emit light, and the shutter 40 has a lower limit on the low speed side as compared with the program auto mode suitable for land photography. The seconds are shifted faster than the program auto mode. Therefore, in the underwater wide mode and the underwater macro mode, the contribution of exposure with flash light is increased, and there is no uneven color covering due to external light, and an image with a well-balanced color can be obtained.
Also, in the underwater macro mode and underwater wide mode, the low-speed side limit time is fixed at the high-speed side compared to the program auto mode and flash photography is performed. The distance becomes longer and the shooting range with flash light is expanded.

  In the shooting mode suitable for underwater shooting, the low-speed limit time of the shutter is set higher than in the program auto mode suitable for shooting on land, so that camera shake is prevented and shooting without camera shake is possible.

  Also, in underwater shooting modes such as underwater wide mode and underwater macro mode, for example, the color temperature is white balance with a (correction) coefficient peculiar to underwater shooting based on 5500K of sunlight (natural light) in fine weather. For this reason, the blue color can be enhanced, and the blue color can be taken with emphasis on underwater photography.

  The above-described embodiments are for explaining the present invention, and the present invention is not limited to the embodiments, and it can be modified and applied without departing from the gist of the present invention. Not too long.

  According to the present invention, there is no uneven color covering due to external light in the underwater shooting mode, and the present invention can be widely applied to optical shooting devices such as a digital camera and a digital video camera having the underwater shooting mode.

1 shows a schematic diagram of an optical imaging device embodied as a digital camera. The external shape of a digital camera is shown, (A) is a plan view, and (B) is a rear view. An LCD screen for selecting and setting an underwater shooting mode is shown. (A) shows a screen before selection, and (B) shows a screen after selection. An example of various conditions in the underwater wide mode, the underwater macro mode, and the program auto mode is shown. The flowchart of a scene mode is shown. An example of the coefficients αs, βs, and γs in the table of the white balance control circuit is shown.

Explanation of symbols

10 Digital camera (optical photography equipment)
12 Shooting lens 14 Image sensor (CCD)
16 Control circuit (adjustment means)
18 White balance calculation circuit (adjustment means)
20 Recording media 22 Memory 24 Release switch (Release SW)
26 Zoom switch (Zoom SW)
28 Flash 30 Liquid crystal display (LCD)
32 Depth gauge 34 Power switch (Powers SW)
36 Mode Dial (Mode SW)
38 Four-way controller (selection key; selection means)
40 Shutter 42 Photometric sensor

Claims (5)

In optical photography equipment that can set shooting mode suitable for land photography and photography mode suitable for underwater photography,
A flash device that emits flash light to the subject;
A photometric sensor that detects the amount of light in the subject;
A shutter for adjusting the amount of light at the time of shooting,
Control means for controlling the shutter and the flash device based on the detection result of the photometric sensor to execute a photographing operation;
Comprising
When the mode suitable for underwater photography is set, the control means forcibly causes the flash device to emit light, and sets the low-speed limit time of the shutter to a higher speed than in the mode suitable for land photography. An optical photographing device characterized by shifting to a position. 2. The optical photographing apparatus according to claim 1, wherein when a mode suitable for underwater photographing is set, a low-speed limit time of the shutter is fixed. Adjustment means for adjusting the white balance of the captured image;
A selection means for selecting an underwater shooting mode;
Further comprising
3. The optical photographing apparatus according to claim 1, wherein the adjusting unit adjusts the white balance so as to emphasize the blue component when the underwater mode is selected. 4. A digital camera according to claim 3, wherein said adjusting means has an auto white balance function for adjusting white balance based on a photographed image. 5. The optical system according to claim 3, wherein the adjusting means performs white balance adjustment based on a color temperature in fine weather instead of the auto balance function when the underwater shooting mode is selected. Shooting equipment.

Images